1. Field of the Invention
The present invention relates to an improved method of effecting enhanced penetration of wood preservatives into wood and, more specifically, it relates to such a method which employs a buffered compound which facilitates enhanced penetration of wood preservatives into the wood.
2. Description of the Prior Art
It has been known for many years to treat wood with materials which will protect the wood from deterioration. Among such approaches have been surface painting or the use of materials which will penetrate into the wood as by pressure impregnation or vacuum application. Among the materials used are fungicides, insecticides, decay-resisting materials, stain-resisting materials, weather proofing materials and others. See, for example, U.S. Pat. Nos. 4,879,083; 4,950,685; 5,468,284; 5,763,338; 5,833,741; 5,855,817; 5,972,266; 6,416,789 and 6,582,732.
In pressure and vacuum methods, the wood is treated with water or solvents that carry preservatives. The pressure or vacuum methods cause the wood to pick up large amounts of these carriers and, as a result, require kiln drying or oven drying or long-term air drying to allow the wood to be useful. Such drying of pressure or vacuum-treated wood using water as a carrier can cause structural defects such as warping, cracking and checking.
It has been known to suggest the use of amine oxides in combination with other materials in wood preservatives. See, for example, U.S. Pat. Nos. 6,274,199; 6,375,727; 6,448,279 and 6,527,981.
It has also been known to introduce into woods materials for fire-retardant properties. U.S. Pat. No. 6,811,731 discloses fire retardant protection achieved by treating green wood with a phosphate/borate.
It has also been known to suggest the combination of an amine oxide with a boron compound with the boron compound employed in a large enough amount to function as a preservative in wood. See U.S. Pat. No. 5,846,305; United States Published Patent Application No. 2002/0065206, now U.S. Pat. No. 6,508,869.
In the use of known prior art systems which required pressure impregnation or vacuum, capital investment for the equipment needed to achieve the desired pressure relationship influenced the economics of introduction of wood-preservative materials. Also, some prior art systems employed volatile solvents which presented environmentally undesirable conditions. In addition, such solvents added to the cost of such procedures. An example of such undesirable materials is petroleum distillates.
U.S. Pat. No. 7,655,281 discloses a method of protecting wood through enhanced penetration of wood preservatives by providing a solution which includes at least one amine oxide, at least one organic wood preservative, and a buffering agent. The buffering agent is selected from the group consisting of borates, boric acids, and combinations thereof.
There remains, therefore, a need for alternate means for effectively achieving the desired level of penetration of wood preservatives while having favorable economic aspects and avoiding risks to human health and environmentally-undesirable conditions.